RESUMO
OBJECTIVE: To develop a statistical method for defining clusters of necrotizing enterocolitis (NEC) cases in the neonatal intensive care unit (NICU). STUDY DESIGN: The study group included 2782 infants weighing 401 to 1500 g at birth born between 1996 and 2004. NEC was defined as Bell stage II or III. Two statistical methods were used to define "disease clusters": a modified scan test and a comparison of observed and expected incidence density rates (IDRs) of NEC at each NICU. RESULTS: The proportion of infants with NEC was similar in the 2 NICUs (7.1% vs 7.7%; P = .6), as was the expected IDR of NEC (1.39/1000 patient-days vs 1.32/1000 patient-days; P = .72). Twelve temporal clusters of NEC were identified in the 2 NICUs, representing 18% of 203 total NEC cases during the study period. No seasonal/secular trends were noted for NEC rates or identified clusters. Potential NEC clusters of > or =3 cases at either NICU had a >75% likelihood of being a true NEC cluster. CONCLUSIONS: No operational definition of NEC cluster exists. This study introduces methods to use in prospective surveillance and to guide studies investigating etiologic relevance. Using the proposed methods, statistically significant clusters (ie, potential outbreaks) of NEC within NICUs can be identified early, providing an opportunity for early implementation of cluster investigation protocols.
Assuntos
Surtos de Doenças/estatística & dados numéricos , Enterocolite Necrosante/epidemiologia , Doenças do Recém-Nascido/epidemiologia , Humanos , Incidência , Recém-Nascido , Recém-Nascido de muito Baixo Peso , Unidades de Terapia Intensiva Neonatal , Ohio/epidemiologia , Estudos Retrospectivos , Estações do AnoRESUMO
We sought to determine whether the interval between menarche and age of first sexual intercourse is associated with subsequent human papilloma virus (HPV) infection and if so, whether the association is independent of the age of first sexual intercourse. Female university students completed a survey and were screened for cervicovaginal HPV infection. HPV-positive subjects were matched to HPV-negative subjects (n = 504). Mean subject age was 20.4 +/- 2.1 years, age of first sexual intercourse 16.7 +/- 1.8 years, and interval 4.4 +/- 2.0 years. The interval was associated with HPV infection, but the association became nonsignificant in univariate stratified analyses and multivariate models estimating the association between the interval and HPV infection. A short interval is associated with HPV infection, but the association is not independent of age of first sexual intercourse. Age of first sexual intercourse should be considered an important and identifiable risk factor for subsequent HPV infection in research and clinical settings.